jtbel Posted April 15, 2011 Share Posted April 15, 2011 I am having to give it gas on start up to prevent stalling until it is warm. I replaced the coolant temperature sensor with a new one. And, the iacv with a used one, with no change. Will the egr valve cause this problem? And if so, even though the egr pipe is blocked off? If not, what else could cause this cold start up problem? After a couple minutes when it warms up, it will run fine. Quote Link to comment Share on other sites More sharing options...
jtbel Posted April 16, 2011 Author Share Posted April 16, 2011 Any mechanics around? I prefer to fix it myself instead of taking it somewhere. Thanks Quote Link to comment Share on other sites More sharing options...
curiousB Posted April 17, 2011 Share Posted April 17, 2011 Any mechanics around? I prefer to fix it myself instead of taking it somewhere. Thanks A few thoughts. - replacing IACV with a used one might not be good enough. If they are dirty and sticking they won't run properly and you won't get the increased idle during warm up. Make sure its clean and valve is not binding. - there are two temp sensors in some models. One is for the ECU and one is for the dash temperature guage. Poor warm up could be due to the ECU coolant sensor being faulty. Maybe you changed the wrong one. - maybe fuel pressure is low due to a sticky/worn fuel pump that improves as it warms up. Get a $15 fuel pressure guage and see what fuel pressure is on a cold start. - dirty throttle body. This is usually an erratic idle symptom but if its caked up with carbon its a good maintenance item to do anyway. Quote Link to comment Share on other sites More sharing options...
jtbel Posted April 17, 2011 Author Share Posted April 17, 2011 Thanks a bunch for the reply. I made sure both of the iacv's were clean. I changed out the sensor with the 2 wires ( I believe the one going to the ecu). The other sensor has one wire ( I believe for the gauge). The throttle body is clean. The fuel pressure is a good idea, how would I do that? Where would I connect the gauge, and what should the pressure be? By the way, I just changed the fuel filter. Quote Link to comment Share on other sites More sharing options...
curiousB Posted April 18, 2011 Share Posted April 18, 2011 Thanks a bunch for the reply. I made sure both of the iacv's were clean. I changed out the sensor with the 2 wires ( I believe the one going to the ecu). The other sensor has one wire ( I believe for the gauge). The throttle body is clean. The fuel pressure is a good idea, how would I do that? Where would I connect the gauge, and what should the pressure be? By the way, I just changed the fuel filter. 44-50 PSI is expected reading... Most gauges come with various adapters to tap into the fuel rail. Quote Link to comment Share on other sites More sharing options...
jtbel Posted April 20, 2011 Author Share Posted April 20, 2011 I picked up a fuel pressure gauge. I did'nt see a schrader valve on the fuel rail. Can someone tell me the easiest place to connect the gauge (front or back, left side or right side), to check the fuel pressure. Thanks Quote Link to comment Share on other sites More sharing options...
jtbel Posted April 23, 2011 Author Share Posted April 23, 2011 Anybody have any ideas of where the fuel pressure should be checked? Quote Link to comment Share on other sites More sharing options...
curiousB Posted April 24, 2011 Share Posted April 24, 2011 Try to tap into fuel rail anywhere after the fuel filter and before the fuel pressure regulator. Your pressure gauge should have come with various fittings and adapters to tap in. There is no schrader valve for this. This diagram gives a few ideas on where you could tap in. Quote Link to comment Share on other sites More sharing options...
ajg2business Posted May 6, 2011 Share Posted May 6, 2011 I'm having the same problem with my 1992 LS400 271K miles. I replaced the iacv. After giving it a little gas at start up my idle is a little low. My throttle body is clean, and plenty of fuel pressure. What can I check next? Quote Link to comment Share on other sites More sharing options...
curiousB Posted May 7, 2011 Share Posted May 7, 2011 Well maybe vacuum leak. That would pass air and lean out fuel mix as the MAF doesn't detect leaking air so doesn't add proportional fuel to go with it. Loosely fitted air duct or broken off vacuum line? Was starter motor worked on lately? Sometimes folks try to reuse manifold gasket with poor results. Quote Link to comment Share on other sites More sharing options...
jtbel Posted May 9, 2011 Author Share Posted May 9, 2011 I had replaced the starter a few months back, and I reused the gaskets. So, a vacuum leak is a very real possibility. Once the car is warm, it will run fine. Though I have'nt checked recently, what I can't understand is why the code for the driver side cam sensor kept popping up shortly after erasing it. I had just installed a new sensor. One would think that it is working properly given that once the car is warm it drives fine. I'm not sure, but I don't think the cam sensor would be related to a cold start issue. Quote Link to comment Share on other sites More sharing options...
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